In a strict sense a pubic hair would be considered trace evidence found at the scene and not some sort of signature much less part of the modus operandi.

The use of pliers of a certain type which are left at the scene would be MO for the pliers and possibly MO rather than signature if they are left at the scene. Certainly if a pink ribbon is tied around the pliers that pink ribbon becomes a 'signature' since it is a totally needless act as far as the murder goes.

A pubic hair would be 'signature' if it were intentionally and prominently placed at the scene of the crime.

I don't see other similar crimes in the intervening seven years. No other useless and lengthy notes.

No common MO either: no home invasion with use of cord and implement from home to molest.